Low foaming detergent for automatic dishwashing machine



United States Patent 7 3,022,250 LL'OW .FOAMING DETERGENT FOR AUTOMATIC DISHWASHHNG 'MACHINE Richard A. Grifo, Easton, Pa, and Raymond LkMayhew,

Phillipsburg, Ni,'assignorsto'General Aniline Sz Film Corporation, New Yorlg'NzY, a corporation'of Dehware No-Drawing. Filed'llanpl'tl,1%8;Ser. No. 708,066

v2 Claims. ((31. 252-135) The 'invention here presented is anew and usefullowfoaming, low-sudsing detergent, especially adapted for automatic dishwashing machines, in the form of asubstituted phenol containing a chain of a critical number of ethylene oxidemolecules.

Variousof the automatic dishwashing machines impose rather severelimitations upon "the detergent whichcan be used therein, and low-foam detergents are required in order to avoid interference with 'the mechanical operation of the washer and to permit of clean 'rinsin'g'vvi'th the facilities available in the machine. To 'thepresent, none of the available detergents arefound to be fully-satisfactory. One of the'better di'shwashing machines uses a rotating arm carrying a jet on the end thereof, through which detergent solution is forced in the form of a spray or stream which serves the dual purpose of applying'detergent solution to the dishes and of 'rotating the arm so that the'spray travels under the dishes and giveseach one a vigorous application of detergent solution-by 'the utilization of'ajet or'spray under considerable pressure. -However, it has notbeen found mechanically convenient to drive the spray by power, because of the danger'of breaking any silver or dish which may dropthroughthe'tray into the path of the jet, and it is accordingly essential that the jet shall be flexibly driven -so-that it-will'stop, if an impediment is in the path, without breaking dishes or bending s'ilver.

Accordingly, a swinging arm'is lightly'journaled'in the bottom of the washer, belowthedishes, and the reaction pressure in the jet is utilized-to spin'the journal arm and ensure coverage of all of the 'dish surfaces. In addition, it isnecessary that a minimum-of water spots-beleft on glassware washed in the machine,-which meansthat the detergentsolution must be of-such character that it can be very easily rinsed off fromthe dishes. In'view of this situation, a high-foam-detergent is contraindicated, since a thick suds may stop the swinging arm entirely, and a thick suds'is dilficult'to rinse ofi'from glassesand dishes.

According to the present invention,it is now found that an'alkyl substituted phenol, havingfrom 8 to 12 carbon atoms in the alkyl chain, and a polyoxyethylenechain containing, on the average, an amount of ethylene oxide within the range between 40% to 47% of the ethylene oxide, is highly etfective since it yields a very low suds,'too low in quantity toiinterfere with the rotation of the jet arm and lowenough to be easily rinsed off of bothglassware and dishes by a jet of clear water through thesame swinging arm and spray head; and at the same'time has a powerful detergentaction, strong enough.to ensure a complete freeingof all traces of grease and'other adherent matter from dishes-andglasswa're. j

It will be observed that a maximum detergent'power is called for, together with a minimum of suds, and his found that this requirement sets a sharply critical series of limitations upon the composition of the detergent. Thus the base is phenol containing an aliphatic-substituent which is predominantly nine carbon atoms long, and averages, in analysis, close to nine atoms, minor quantities of other phenols being permissible. With this there are then combined ethylene oxide molecules to form a polyoxyethylene chain, which, again, is critical in length and preferably contains a major proportion of four ethylene oxide molecules, although minor proportions of three the detergent solution is pumped, the revolutions per minute of the arm which can be measured easily is dependent on the amount of foam produced from the solution, so that'anexcess of foam will actually stop the machine. "Consequently, a decrease in'r.p.m. signifies an increase in foam. I

The dishwashing or water spotting performance of the products was tested by washing glass tumblers in the above-mentioned dishwasher together with the product to be tested and a greasy soil consisting of oleomargarine and Starlac (powdered skim milk). The glass tumblers are rated according to the number'of dried water spots remaining on the tumblers. In order to compare the various products'teste'd' on an equal'basis, the data reported relative to nonylphenol 4 moles.ethylene.oxide which tion will be'apparent from the following description:

The firstcomponentof the substance of the invention -1s-a-nonylphenol,- which is'availableon' the 'open market or may be prepared by alkylation of phenol. For this purpose the phenolcontaining the alkyl substituent is treated with a'suitable amount of ethylene oxide, as is well shown in United States Patent No. 2,213,477, to yield the type of, polyoxyethyleneglycol -phenol etherthereindis- .closed. The resulting compound of nonylphenol'with 4 "moles of ethylene oxide per mole-of -nonylphenol is the primary component of the invention. 'It maybe noted, 'as above pointed out, that none of'these reactions yield single pure substances, and accordingly the amount" stated -is=prese'nt ina major 'propo'rtiom butnearly always is accompanied by minor propoi-tions of the-higher and lowerra'tio compounds; and as long as the desired compound is p'resent inrna'j-or' proportion, and analysis shows an average number of ethylene oxide molecules, the exactamount and'ex-act size'of substituents'is'of minor or"negligibleconsequence. This compound is the base of the composition ofthe "invention.

This compound of nonylphenol and ethylene oxide,in the proportions above'indicated, is an excellent detergent; but it is found, further, that its detergent power can be substantially increased by the procedure of building the detergent, by which procedure the liquid nonylphenol ethylene oxide compound can be converted from a viscous liquid to a nearly solid granular compound if desired. This procedure involves the addition to the nonylphenol ethylene oxide compound of appropriate auxiliary sub stances, such as sodium metasilicate, trisodium phosphate, sodium tripolyphosphate, sodium pyrophosphate, sodium hexametaphosphate, and the various other polyphos- 3 phates, as well as various other substances which are well known in the art.

EXAMPLES Fourteen tests were run on various proportions and sizes of the respective substituents on the phenol grouping, yielding 14 separate examples. The results are shown in the following table, in which the composition of the detergent is indicated in the first column, the percentage of ethylene oxide present is indicated in the second column, the revolutions per minute of the agitator in the washer is shown. The last column shows the relative intensity of water spotting, all as above outlined.

Mechanical dishwashing evaluation [Tapwater temp. at 140 )3. Product conc. 0.25%]

Water Spotting Relative to N onylphenol +4 Moles Ethylene Oxide Equal to 100 Foam, r.p.m. oi Agitator Surfactant Percent EtO Nonylphenol-l-1% E.O

Nonylphenol+5 E.O Nonylphenol-l-fi E.O Nonylphenol+9 E.

Dinonylphenol+7 E.d.

The surfactant in each instance was built. by mixing 5% of the indicated surfactant, or detergent, with 95% of a builder, consisting of one part sodium metasilicate with 3 parts of sodium tripolyphosphate.

Similar tests were applied to detergents available on the market, the exact composition of each being unknown other than the fact that each lacked any ethylene oxide substituent. The results are shown in the following table:

Mechanical dishwashing evaluation [Tapwater temp. at 140 F. Product cone. 0.25%]

7 Water Spot- Foam, ting Relative to Surfactant Percent r.p.m. 1\'onylpl1enol EtO Agitator +4 Moles Ethylene Oxide Equal to 100 Triton CF-IO 0 75 100 Chat (as is).-- 0 50 105 Calgonite (as 0 80 220 Cascade (as is) 0 Builders alone 0 90 170 arm dishwasher, which is known to require very carefully adapted detergent, substituted phenols, containing 4 molecules of ethylene oxide, were uniformly critical in proportion and were the only ones which produced detergent which did not interfere with the rotation of the jet arm, and at the same time gave a good freedom from water spots upon rinsing.

Thus the invention consists of a low-foam detergent in the form of a benzene ring having thereon an aliphatic substituent having an average chain length of 9 carbon atoms, and a second substituent in the form of a condensation product of ethylene oxide containing an average of 4 ethylene oxide molecules per molecule of nonylphenol; the mixture being conveniently combined with suitable builders for use in a swinging-arm dishwasher machine.

While there are above disclosed but a limited number of embodiments of the invention, it is possible to produce still other embodiments without departing from the inventive concept herein disclosed, and it is therefore desired that only such limitations be imposed upon the appended claims as are stated therein or required by the prior art.

The invention claimed is:

1. A low-foam detergent composition for use ina swinging-arm dishwasher consisting essentially of a phenol having therein an aliphatic substituent with an average number of 9 carbon atoms per chain, and a second substituent comprising condensed ethylene oxide in an average number of 4 molecules per molecule of phenol together with builders consisting essentially of a mixture of sodium metasilicate and sodium tripolyphosphate in the proportion of one part of metasilicate to three parts of tripolyphosphate, the builders being present in the proportion of parts of builder mixture to 5 parts of nonylphenol ethylene oxide.

2. A low-foam detergent composition for use in a swinging-arm dishwasher consisting essentially of a phenol having therein an aliphatic substituent with an average number of 9 carbon atoms per chain, and a second substituent comprising condensed ethylene oxide in an average number of 4 molecules per molecule of phenol together with builders consisting essentially of a mixture of sodium metasilicate and sodium tripolyphosphate in the proportion of one part of metasilicate to three parts of tripolyphosphate, the builders being present in the proportion of 95 parts of builder mixture to 5 parts of nonylphenol ethylene oxide, together with water in an amount equal to 400 times, by weight, of the amount of nonylphenol and builders together.

References Cited in the file of this patent UNITED STATES PATENTS Steindorfi Sept. 3, 1940 Black May 29, 1951 OTHER REFERENCES 

1. A LOW-FOAM DETERGENT COMPOSITION FOR USE IN A SWINGING-ARM DISHWASHER CONSISTING ESSENTIALLY OF A PHENOL HAVING THEREIN AN ALIPHATIC SUBSTITUENT WITH AN AVERAGE NUMBER OF 9 CARBON ATOMS PER CHAIN, AND A SECOND SUBSTITUENT COMPRISING CONDENSED ETHYLENE OXIDE IN AN AVERAGE NUMBER OF 4 MOLECULES PER MOLECULE OF PHENOL TOGETHER WITH BUILDERS CONSISTING ESSENTIALLY OF A MIXTURE OF SODIUM METASILICATE AND SODIUM TRIPOLYPHOSPHATE IN THE PROPORTION OF ONE PART OF METASILICATE TO THREE PARTS OF TRIPOLYPHOSPHATE, THE BUILDERS BEING PRESENT IN THE PROPORTION OF 95 PARTS OF BUILDER MIXTURE TO 5 PARTS OF NONYLPHENOL ETHYLENE OXIDE. 